I can. The only argument that stands up among those is the 'costing' one; WSMR should consider, as Virgin do, their passengers to be adult enough to make their own descisions on whether to drink or not (which, if they are driving after the journey, they might choose not to).
So it's purely down to cost, then?
I used to travel British Airways a lot to Heathrow, business class. That gave use of the business lounges, which not only had free food and drink available, but it was a 'help yourself' bar. Even with an unending supply of free self-serve booze available, I never saw anyone abuse it. Although I do recall one evening coming home, when due thunderstorms a lot of flights were delayed by up to 4 hours; the witty girl on reception was keeping everyone updated over the public address as to progress with our flights, and also added from time to time reminders that those driving after their flights should take it easy on the G&Ts!